Not The Pilot

NOT the pilot has charged himself to bring his ship into port, though
  beaten back, and many times baffled;
Not the path-finder, penetrating inland, weary and long,
By deserts parch'd, snows-chill'd, rivers wet, perseveres till he
  reaches his destination,
More than I have charged myself, heeded or unheeded, to compose a
  free march for These States,
To be exhilarating music to them-a battle-call, rousing to arms, if
  need be-years, centuries hence.